Individuals suffering from a central nervous system injury, such as a stroke, a brain injury, multiple sclerosis, cerebral palsy or partial spinal cord injuries, or other medical conditions may have mobility problems due to that injury or medical condition. Functional electrical stimulation (FES) systems may assist those individuals address those mobility problems.
Existing FES systems provide electrical stimulation to muscles that may have been paralyzed or affected by the central nervous system injury or other medical conditions. The electrical stimulation may facilitate motion in those affected muscles. In some cases, FES systems may also help reeducate muscle movement, retard atrophy of any affected muscles due to disuse, and maintain or increase a range of motion at nearby joints.
An example application of an FES system is to enhance ankle dorsiflexion for individuals experiencing foot drop. Foot drop is a gait abnormality that stems from a weakness in a foot, damage to a peroneal nerve, or paralysis of muscles in an anterior portion of a lower leg. Foot drop may be caused by various conditions, such as muscle or spinal nerve trauma, abnormal anatomy, toxins and disease. Individuals affected by foot drop are unable to lift their foot and toes during a swing phase of their gait thereby causing their toes to be caught by the ground and their foot to drag on the ground. The FES system can assist those individuals by sending electrical stimulation signals to the affected muscles during the swing phase of their gait in order to trigger movement in those muscles so that the foot is lifted and not dragged along the ground.
Although existing FES systems are generally portable, they tend to be bulky and therefore, cumbersome for users to carry around on a daily basis. Existing FES systems also tend to lack versatility in operation and offer limited functionality.